Auth0 can be used that way but with some work. It really shines when you want to build saas that requires user login. Auth0 is worth every penny (priced by active logins) but I’d be hard pressed to spend 4$ per user if I’m building a consumer saas (but 4$ per employee login is reasonable).
Really big companies will often have multiple AD/LDAP identity stores with enterprise grade provisioning systems (Sailpoint, Oracle Identity Manager) to keep accounts in sync.
This offering from Google is meant as a replacement for AD/Exchange(obviously) for companies that are mid-small. It also offers provisioning to other apps but only those that support SAML Just-In-Time provisioning. I did not immediately see a way to add custom apps to this (for provisioning), so might be limited to just the OOTB apps they provide (List: https://support.google.com/cloudidentity/topic/7661972)
Auth0 today offers SAML integrations and if the target system supports JIT Provisioning, it will work the same as google.
And just to clarify, Google's offering is 100% meant for internal users (employees, anyone that you'd give a Google Apps account to)
Edit: BTW, I see this can be set up for Github Business. Does github.com not support SAML?
https://aws.amazon.com/blogs/security/how-to-set-up-federate...